In a coulometric chloride titration, how is the endpoint detected?

In a coulometric chloride titration, the endpoint is detected by amperometry. This method involves measuring the current flow in the solution as chloride ions are titrated. As the titrant is added, the current changes in response to the concentrations of chloride ions present. At the endpoint, a specific change in the current indicates that all the chloride has reacted, allowing for precise determination of the chloride concentration in the sample.

Amperometry is particularly effective for endpoints in titrations because it provides real-time data and high sensitivity, which is essential when detecting the minute changes that occur at the conclusion of the titration. This technique contrasts with visual observation or color change methods, which may be subjective or less accurate, and pH measurement, which is not applicable in this context since the primary reaction does not significantly affect the pH. Thus, amperometry is the preferred method for detecting the endpoint in a coulometric chloride titration.